AME 52:1-11 (2008)  -  DOI:

Comparative actinomycete diversity in marine sediments

Alejandra Prieto-Davó, William Fenical, Paul R. Jensen*

Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093-0204, USA
*Corresponding author. Email:

ABSTRACT: The diversity of cultured actinomycete bacteria was compared between near- and off-shore marine sediments. Strains were tested for the effects of seawater on growth and analyzed for 16S rRNA gene sequence diversity. In total, 623 strains representing 6 families in the order Actinomycetales were cultured. These strains were binned into 16 to 63 operational taxonomic units (OTUs) over a range of 97 to 100% sequence identity. The majority of the OTUs were closely related (>98% sequence identity) to strains previously reported from non-marine sources, indicating that most are not restricted to the sea. However, new OTUs averaged 96.6% sequence identity with previously cultured strains and ca. one-third of the OTUs were marine-specific, suggesting that sediment communities include considerable actinomycete diversity that does not occur on land. Marine specificity did not increase at the off-shore sites, indicating high levels of terrestrial influence out to 125 km from shore. The requirement of seawater for growth was observed among <6% of the strains, while all members of 9 OTUs possessed this trait, revealing a high degree of marine adaptation among some lineages. Statistical analyses predicted greater OTU diversity at the off-shore sites and provided a rationale for expanded exploration of deep-sea samples. A change in community composition was observed, with the number of Micromonospora OTUs increasing in the off-shore samples. UniFrac (see statistics support a difference in community composition between near- and off-shore locations. Overall, 123 of 176 strains had distinct 16S rRNA gene sequences, indicating a high level of actinomycete diversity in marine sediments.

KEY WORDS: Marine actinomycetes · Marine sediments · Bacterial diversity · Seawater requirements · Phylogeny

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Cite this article as: Prieto-Davó A, Fenical W, Jensen PR (2008) Comparative actinomycete diversity in marine sediments. Aquat Microb Ecol 52:1-11.

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